Survey report: control technology evaluation for controlling worker exposure to asphalt fumes from roofing kettles: kettle operated using an afterburner system at Tampa Bay Technical High School, and West Park Village at West Chase, Tampa, Florida, report no. CT-231-17a.
On September 11 through 13, 2001, two field surveys were conducted at sites where built up asphalt roofs were being installed. One survey was conducted at Tampa Bay Technical High School in Tampa, Florida where cap sheet was being installed on top of a recently installed built up asphalt roof. The other survey was conducted at West Park Village at West Chase in Tampa, Florida, a construction site where a built up asphalt roof was being installed on a new apartment/business building. The surveys were conducted to evaluate the effectiveness of an afterburner system with a safety loading door on an asphalt kettle to reduce worker exposure to asphalt fumes. The kettle used at the Tampa Bay Technical High School was equipped with an afterburner system and safety loading door, and all of the asphalt was added through the safety loading door. The kettle used at the West Park Village was not equipped with any engineering controls to reduce asphalt fume emission, and the kettle lid remained open the entire work day. Personal breathing zone and area air samples were collected and analyzed for total particulate (TP), benzene soluble fraction (BSF) of the TP, and total polycyclic aromatic compounds (PAC). These three analyses were chosen to represent indices of exposure to asphalt fumes. Air samples were collected on the kettle operator and two roof level workers; area air samples were collected around the four comers of the kettle. The kettle operator's exposures at the Tampa Bay Technical High School to TP, BSF, and total PAC were all less than the exposures measured for the kettle operator at West Park Village. The percent differences between the two kettle operators' exposures to TP, BSF, and total PAC were 94%, 97%, and 91%, respectively. Percent differences of 97%, 98%, and 98% in TP, BSF, and total PAC were measured for the area air samples collected around the two kettles. For the roof level workers, exposures to TP, BSF, and total PAC were 28%, 10%, and 48% higher for the workers at the Tampa Bay Technical High School when compared to the workers at the West Park Village. The percent differences in exposures for the kettle operators and the area air samples collected around the kettle were all statistically significant (p less than or equal to 0.05). The asphalt fume concentrations measured for the kettle operator and the area samples collected around the kettle were all significantly lower at the site where the control was in use than at the site with no control. The major limitation on these findings is that the comparison was made between different sites using two different types of kettles. The differences in exposures seen between the two sites for the kettle operators and the area air samples collected around the kettle were not seen when comparing the roof level workers. Exposures were higher for the roof level workers at the Tampa Bay Technical High School.
National Institute for Occupational Safety and Health, Division of Applied Research and Technology, Mail stop R-5, 4676 Columbia Parkway, Cincinnati, OH 45226